Fix the problem that notifications and panels overlap.

chrome/browser/notifications/balloon_collection_impl.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Handles the visible notification (or balloons).
 
 #ifndef CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_IMPL_H_
 #define CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_IMPL_H_
 #pragma once
 
 #include <deque>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "chrome/browser/notifications/balloon_collection.h"
 #include "chrome/browser/notifications/balloon_collection_base.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/rect.h"
 
 // Mac balloons grow from the top down and have close buttons on top, so
 // offsetting is not necessary for easy multiple-closing.  Other platforms grow
 // from the bottom up and have close buttons on top, so it is necessary.
 #if defined(OS_MACOSX)
 #define USE_OFFSETS 0
 #else
 #define USE_OFFSETS 1
 #endif
 
 // A balloon collection represents a set of notification balloons being
 // shown on the screen.  It positions new notifications according to
 // a layout, and monitors for balloons being closed, which it reports
 // up to its parent, the notification UI manager.
-class BalloonCollectionImpl : public BalloonCollection
+class BalloonCollectionImpl : public BalloonCollection,
+                              public content::NotificationObserver
 #if USE_OFFSETS
                             , public MessageLoopForUI::Observer
 #endif
 {
  public:
   BalloonCollectionImpl();
   virtual ~BalloonCollectionImpl();
 
   // BalloonCollection interface.
   virtual void Add(const Notification& notification,
                    Profile* profile);
   virtual bool RemoveById(const std::string& id);
   virtual bool RemoveBySourceOrigin(const GURL& source_origin);
   virtual void RemoveAll();
   virtual bool HasSpace() const;
   virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size);
   virtual void SetPositionPreference(PositionPreference position);
   virtual void DisplayChanged();
   virtual void OnBalloonClosed(Balloon* source);
   virtual const Balloons& GetActiveBalloons();
 
+  // content::NotificationObserver interface.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
   // MessageLoopForUI::Observer interface.
 #if defined(OS_WIN) || defined(TOUCH_UI) || defined(USE_AURA)
   virtual base::EventStatus WillProcessEvent(
       const base::NativeEvent& event) OVERRIDE;
   virtual void DidProcessEvent(const base::NativeEvent& event) OVERRIDE;
 #elif defined(TOOLKIT_USES_GTK)
   virtual void WillProcessEvent(GdkEvent* event) OVERRIDE;
   virtual void DidProcessEvent(GdkEvent* event) OVERRIDE;
 #endif
 
@@ skipping 53 matching lines @@
                             gfx::Point* position_iterator) const;
 
     // Return a offscreen location which is offscreen for this layout,
     // to be used as the initial position for an animation into view.
     gfx::Point OffScreenLocation() const;
 
     // Returns true if the layout requires offsetting for keeping the close
     // buttons under the cursor during rapid-close interaction.
     bool RequiresOffsets() const;
 
+    // Returns true if there is change to the offset that requires the balloons
+    // to be repositioned.
+    bool ComputeOffsetToMoveAbovePanels(const gfx::Rect& panel_bounds);
+
    private:
     // Layout parameters
     int VerticalEdgeMargin() const;
     int HorizontalEdgeMargin() const;
     int InterBalloonMargin() const;
 
+    bool NeedToMoveAboveLeftSidePanels() const;
+    bool NeedToMoveAboveRightSidePanels() const;
+
     // Minimum and maximum size of balloon content.
     static const int kBalloonMinWidth = 300;
     static const int kBalloonMaxWidth = 300;
     static const int kBalloonMinHeight = 24;
     static const int kBalloonMaxHeight = 160;
 
     Placement placement_;
     gfx::Rect work_area_;
+
+    // The offset that guarantees that the notificaitions shown in the
+    // lower-right or lower-left corner of the screen will go above currently
+    // shown panels and will not be obscured by them.
+    int offset_to_move_above_panels_;
+
     DISALLOW_COPY_AND_ASSIGN(Layout);
   };
 
   // Creates a new balloon. Overridable by unit tests.  The caller is
   // responsible for freeing the pointer returned.
   virtual Balloon* MakeBalloon(const Notification& notification,
                                Profile* profile);
 
   // Gets a bounding box for all the current balloons in screen coordinates.
   gfx::Rect GetBalloonsBoundingBox() const;
@@ skipping 10 matching lines @@
   // Get the work area on Mac OS, without inverting the coordinates.
   static gfx::Rect GetMacWorkArea();
 #endif
 
   // Base implementation for the collection of active balloons.
   BalloonCollectionBase base_;
 
   // The layout parameters for balloons in this collection.
   Layout layout_;
 
+  content::NotificationRegistrar registrar_;
+
 #if USE_OFFSETS
   // Start and stop observing all UI events.
   void AddMessageLoopObserver();
   void RemoveMessageLoopObserver();
 
   // Cancel all offset and reposition the balloons normally.
   void CancelOffsets();
 
   // Handles a mouse motion while the balloons are temporarily offset.
   void HandleMouseMoveEvent();
 
   // Is the current cursor in the balloon area?
   bool IsCursorInBalloonCollection() const;
 
   // Factory for generating delayed reposition tasks on mouse motion.
   base::WeakPtrFactory<BalloonCollectionImpl> reposition_factory_;
 
   // Is the balloon collection currently listening for UI events?
   bool added_as_message_loop_observer_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(BalloonCollectionImpl);
 };
 
 #endif  // CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_IMPL_H_